Damping plate reduces engine noise at PSA

Trelleborg Automotive has developed a damping plate that allows PSA Peugeot Citroen to reduce noise and vibration caused by diesel-engine knocking.

Trelleborg Automotive used its NVH experience to produce a specially-cut shear plate, engineered using the company’s Duru-LAM material.

Resistant to both heat and oil, Duru-LAM is a proven material for damping sound and vibrations in internal engine applications and, in the shear plate design, it comprises a layer of rubber sandwiched between two layers of steel.

The shear plate is then positioned according to the packaging requirements of different core engine designs and can be used in gasoline, as well as diesel variants.

Arvid Norberg, research and development NVH manager at Trelleborg Automotive, said: ‘The conventional solution to reduce vibration is to increase engine block stiffness, but in many cases this only shifts the noise to higher frequencies.

‘The introduction of the shear plate enables us to reduce vibration and noise levels, resulting in improved sound quality.’ Since receiving shear-plate prototypes from Trelleborg Automotive, PSA Peugeot Citroen has undertaken rigorous acoustic research and simulation testing of the part and has developed a technique that enables ranking of engine sound quality.

Leon Gavric, senior acoustics expert and head of PSA Peugeot Citroen’s Powertrain NVH Department, said: ‘The shear plate filters out unwanted vibrations and knocking noise, but the real gain is that by reducing noise and vibration issues, we can tune the combustion to reduce emissions, pollutants and fuel consumption.

‘As a result, it makes designing higher-performance eco-friendly engines a reality.’ Trelleborg Automotive also expects its shear plate concept to deliver additional cost savings, by reducing the need for other, more expensive and heavier damping solutions.

The company is undertaking further damping tests with its Duru-LAM material, using FEM tools to determine thickness measurements and shear-plate tuning requirements of different engine types.

In addition, Trelleborg Automotive’s shear plate concept is expected to assist manufacturers upon the introduction of new European emission standards, Euro Five and Euro Six.